ウランおよびアクチノウラン系列放射性同位体非平衡系による年代測定法

抄録

If the natural radioactive nuclides of uranium or actinouranium series existed at one time of the past in the situations of the enrichment of either the parent nuclide or the daughter nuclide, the age determination of Quaternary sample in such system can be made by using either the growth of the daughter nuclide to the radioactive equilibrium with its parent or the exponential decay of the daughter nuclide, respectively. The historical review of the applications of these methods to various samples and the discussions of their results are given in the order of the following themes together with the brief description of the methods for the determinations of the concerning nuclides.
I. Uranium or Actinouranium enriched systems or Uranium isotopes disequilibrium system.
1) Ionium (Radium) growth method: (a) coral and oolite, (b) mollusc shell, (c) fossil bone, fossil soil, peat and others, (d) volcanic rocks.
2) Protactinium growth method.
3) Uranium isotopes ratio method.
II. Daughter nuclides enriched system.
1) Ionium decay method and ²³⁰Th/²³²Th ratio method.
2) Ionium-Protactinium ratio method.
3) Protactinium decay method.
4) ²¹⁰Pb (²¹⁰Po) decay method.
III. Methods for the separation and the determination of the nuclides.